Imports of package portutil

PathSynopsis
github.com/pkg/errorsPackage errors provides simple error handling primitives.
github.com/rootless-containers/rootlesskit/pkg/port
netPackage net provides a portable interface for network I/O, including TCP/IP, UDP, domain name resolution, and Unix domain sockets.
regexpPackage regexp implements regular expression search.
strconvPackage strconv implements conversions to and from string representations of basic data types.